[garethsprice]

> A next step might be something close to public transport. Basically minibuses running something similar to shuttles between hotels and airports.

There's also a huge and mostly hidden network of "dollar vans" in cities with large immigrant populations, private operators serving areas not touched by public transport routes. Not saying that Uber will expand this far downmarket, but interesting to note that what you describe exists in some form already.

http://mashable.com/2014/04/10/dollar-vans-new-york/